Automatic telephone switching apparatus.



A. E. KEITH & J. G. BLESSING. Auommc TELEPHGNE swncl-lm APPARATUS.

APPLICATION FILED SEPT. 251914.

Patented Feb. 25, 1919.

A. E. KEITH & J. G. BLESSING. AUTOMATIC TETEPHONE swTTcHTNG APPARATUS.

` AF'PLICTION HLED SEPTlZS |914. 1,295,175. Patented Feb. 25, 1919.

3 SHEETS--SHEE 2.

3 SHEETSSHEEI 3.

Patented Feb. 25, 1919.

A. E. KEITH & 1. G, BLESSING. AUTOMATIC TELEPHONE SWITCHING APPAHAYUS. APPucAnon man SEPT. 25. |914.

UNITED STATES PATENT OFFICE.

ALEXANDER. E. KEITH, OF HINSDALE, AND JOHN G. BLESSING, OF CHICAGO, ILLINOIS,

ASSIGNORS TO AUTOMATIC ELECTRIC COMPANY, 0F CHICAGO, ILLINOIS, A CORPO- RATION 0F ILLINOIS.

AUTOMATIC TELEPHONE SWITOHING APPARATUS.

Application tiled September Q5. 1914.

To all whom if may concern.'

Be it known that'u'e., ALEXANDER E. Kermt and .loiix (l. Bnicssino, citizens ot the United States of America. and residents et Hinsdale. Dnpage county, Illinois, :ind (fin.- cago, Cool; county, Illinois, respectively. have invented certain new and useful Improve iiieiits in Automatic Telephone Switching Apparatus,of ivhieli the 'following isa specicatioii.

Uur invention relates to automatic telephone apparatus. It relates furthermore to automatic switching apparatus, through the medium ntl-Which one line is brought. into connection with another in rrspoi'isc to electrical impulses. Among the special objects oi" our invention are the following: to provide an improved forni of switch sprricilly adapted for use :is what is ordinarilyl known as a rotary switch, or also :is what is ordinarily known as a nonnuniericiil switch. These switches may be used -ior iiidr` idual switches to the subscribers lines. iioilier object of our invention is to provide certain details and features ol improvement teint ing to increase the etliciency and serviceabil` ity ot' apparatus of the` above character. To these ends our invention consists` in the foregoing and certain combinations as here inafter described and more. partiunlarl;V set forth and claimed.

In the accompanying drawings` Figures l and 2 show a complete connection iii an au toniatic telephone system embodying thc principles of our invention. h

Fig. 3 shows a top View of the individual or line switch C.

Fig. 4 shows side View of switch (l. and a cross-section of the bank 10.

Fig. 5 show s a cross-section of the switch C.

Figs, f5, 7 and 8 show in detail various parts4 of the switch C.

The automatic substation A (Fig. 1) oomprises the usual receiver 2. transmitter 3, ringer 4 zuid condenser 5. Beingy an :intoinatic substation. it is also provided with si. suitable @all sending mechanism for con trolling the automatic switchesrhirhniech anisiii is represented diagramniatirally b v a Specification of Letters Patent.

Patented Feb. 25, 1919.

serial No. 563,498.

pair of impulse springs 6 and 7 and an impulseiwheel 8, which latter may be controlled by e dial provided with linger holes, in Such a Way that the impulse springs may be m0- inentarily separated a iiuinber of times corresponding to the respective digits of the number ot' the called subscriber.

As illustrated, the line switch C comprises :i traine i), supported by the bank 10, and to which are attached the end plates 11 and 12. The shaft 13 is supported by the said end pbites in such a way to allow for vertical niort-nient. a. pallet 14 is rigidly connected to the, sliiit't 13. Attached to the upper extrennt)v of the shaft 13 is a hub carrying the wipers 15, 1Q, 17, and 18. The shaft is normally held at the extremity of its upward movement by the spring 19, the tension ot' uliieli may be regulated by the `thuiiih screw 20. The lower end of the shaft carries :i projection .which controls the spi-ings 21, the saine being normally held in enneigement. In addition the frame 9 sup-4 ports the two sets of teeth 22 and 23, between which the pallet 14 operates. The bank 10 consists of an insulating material in ivliii-h are embedded the conducting rings 24. 25. :2o and 2T together with the four groups of contacts V, IV, X, and Y. A solenoid 2S is so placed that it will act upon the shaft 13 in a downward direction. 'Referr-ing to Fig. 4 (in which the switch is at noi-inail, it will be seen that the Wipers 15, 1li. lT, and '18 are removed from the bank,

the pallet 14 is resting between two teeth` in the set 22. and the springs 21 are in engagement. Ilpon the energization of the solenoid the shaft 13 drawn downward, the pallet` 14 loaves the. teeth 22 and en ages the. teeth Q3 (as shown in Fig. 6). It will be seen that this change of position has caused the pallet 14 to move throughA a small angular displareuiciit, and as the pallet is rigidly connected to the shaft 13 it follows that said shaft together with the Wipers 15, 16, 17 and 1S has been given a slight rotary movenient to the left. lVith the shaft 13 in an operated position. the Wipers 15, 16. 17 and 18 are lowered upon their respective rings and contarle. As' sheen in Fig. R, the elia it 123 when operatori raus 4, the spring lll to lie removed from behind spring; 30, time allowing the :ringe 21 to Separate. Upon the denergimion of the solenoid. the shaft 1.5i returns to nor-neil :unl in no doing the pallet 14 leaves the teelii fanti engages the teeth 22 (as Shown .in Fig. This; movement of the pallet 14 has caused it, together with the Shaft 13 and the wipere 15, lil, 17 and 1S, to he rotated through a Small angle to the left when ihe shaft returns'. tu normal, the pro jeetion upon its lower end causes the springe1 21 to close and the Spring 3G to 'ne moved to Snell a` position That the s :ring 29 falls in behind it. By rneane of peculiar oonstruetion, it will heeren that the Springs 21 remain in rentar-t until the Shell i3 hanv very nearly rear-lied the limit of its downward movement and in turn the Springs: .31 remain open until the Shaft 'i3 has ver); nearly reached the limit of its upward ,vnrwement Referring to Fig. l, (in Wliieli the wipers are shown at normal), shoulii Lhe solenoid 28 be energized, the wipers: 15, 1B, 1? and 18 would he lowrrerl upon the hunk and then lgiven a slight angular motion in a clockwise direction and a result wiper 15 would Short Contact 8T and romlmfrtor E24, wiper 16 would Short rontarrt 3:2 and conductor 27, Wiper 17 would Short contea-l S5 and conductor Wi per L would short rontact 31 and ronfluetor 2G. Upon the ile* energization ol the Solenoid .28 the Wipers 15, 1G, 17 and lil lroulfl he giron a Slight angular motion in a rleflm'iee tlirerfion and in addition. he raisetl from rontaet nifl; the bank. Thus)l it will he, Heen that in one ronr plete revolution of the shaft 13, the wipers 15, 16, 1T and 1S will have merle rennes?u tion with all of the eontairte in thcl rirrnlar groups V, Ygl/V mul reeprietivrfli'. it will be assumed that Lin minets in groups: V and W are respectively ...he negative and positive line terminals of the if'arious trenini. the contacts in the group X are the terminals of the release Conductor of the various trunks:` while the rentar-*rs in gronp if are the terminals of the elogi elector of the various trunks. It is thus Seen that :is the Wipers l5, 1.6, 17 and 1S engage their rospo@ tive contarte they are given a slight rotary movement, thus insuring a goed. clean fontae.. It will he unflerntooil, of colarse, thatv the various eontalfts engaged hy the wipers at any one time are all asset-interi with the same trunk. For

mstfmre contact 87 would he the negative line. contar-t lf wml be the. positive line, Contact 31 would lie the release conductor and contant would be the stoppin,r conductor of a certain trunk line. Re ferring to Fig. 1 it will he Seen that in addition to the above described apparatus, the line switch C comprises a line relay 3? find a ln'iilne-ci|t-oll relay H8, with suitable Spring assemblies, attached thereto,

The selec-ter ewteli IC (Fig. 1) is of the general ripe of' selector 'switch llisiclr'isecil in Vlfi'rlitml States Letters ljatent No. 815,321, grained March 123', 1906, to Keith, Erickson anti llrielson, except that the circuits are modified to adapt the switch to o emile in a system in which the Central apparatus le controlled by impulses delivered over the two sides on the line in series. iliniong einer details 4the Selector E comprises a bank of eontaets arranged in horizontai rows er levels, which Contacts are :nlaptesl to he engager! by a set of Wipers 3S), Al() and l1 carried upon a Shaft (not shown) which has a vertical movement controllerl by the vertical magnet l2 and a rotary inmfement eonrellerl by the rotary magnet 43. The operations of various parts of the switch are Controlled through the ineflinni ol' the ilouhle wound line relay 44. The usual Side switch comprising the wipers 50, 5l, and 53 is controlled by the private inagne 54 in the usual Well known manner. Means for ,permitting,l the switch to be restored to normal position is provided in the release magnet 45, which, upon energizing attracts :in :lrinuture which in tern willlrlraws the retaining donblodog, from the shaft. The sl'irings 16 close only when the switch shaft has been raised one or more Steps from its lowest poeition. The relays l?, 1S and 49 are slow acting, ,that iS, slow to release their armatures upon deenergizing.

The connector switch H (Fig. 2) is of the saine general type of connector switch as; disclosed in United States Letters Patent No. 815,176, granted March 13, 1906, bo Keith, Erickson and Erickson, the circuits, however. leningi modified to adapt the switch to operate in a system in which the eentrll ,oi-lice apparatus is controlled by impulse@l delivered o ver the two sides of the line in series. Among other details, the connector H eoinprieee a bank of contacts arranged in horizontal ro s or levels, which contacts are adaped to lwipe-,r5.3 55. haml 57 carried upon a Shaft (not shownl which has a vertical movement controlled by the vertical magnet 58 and :1 roary movement controlled by the rotary magnet 59. The usual Side switch comprising the wipers, 60, 61, 62 and 63 is controlled by the private magnet; 64 in the usual ain-l well known manner. The operations of various parts of the switch are controlled through the medium of the line relay 65 in conjunction with the spring assembly thereto attached. Talking battery is supplied lo the Calleri line through the windings of the sri-called beek bridge relay 72. The ringer elay Graffords the means he engaged by e set of by which ringin current is applied to the called line. ll cans for permitting the switch to he restored to normal positions: are provided in the release magnet 67, which, upon energizing, attracts an armature which in turn withdraws the retaining double-dog from the shaft. The springs lin and 69 close only when the switch shaft has been raised one or more steps from its lowest position. The rela \i's 70 and 7l are slow acting-that is, slow to release their armatures upon denergizing. The called substation A (Fig. 2) and its individual line switch C are similar in all re Spects to the calling substation and its individual line switch C.

For the purpose of supplying battery current for operating.,r the apparat us. and 'or talking purposes there is shown the butler;Y B, having one terminal grounded at (l. For the purpose of supplying ringinn current to ring the called substation their i shown the ringing current generator l. 'l fie luis).1 signaling machine Q, as represented herein, comprises an induction coil or transformer, the primary` winding of which is included in a local circuit with a batter;v and a suit able interrupting device. '.l`hrough the medium of this interrupting derive an interrupted current is supplied through the primary Winding, which induces an alternating current in the secondary winding, whereby when Said winding is connected with the subscribers line, a buzzing sound is heard in the receiver.

A general description of the apparatus having been given, it will be now explained how connection can be established between the line of substation A and the line ot' a. called substation A. The number of the called substation will be assumed to be 222.

'Since the automatic switching apparatus disclosed herein is in general well known in the art and is described in the publican tions herein referred to, its operation will be explained in a more or less general manner. i

Upon the removal of the receiver at the calling substation A, (Fig. l), a circuit is formed whichmay be traced from ground G through springs 73 and 74, conductor 75., substation A, conductor 76, springs 77 and 78, relay 37 to battery B. The relay 37, upon energizing, closes a circuit from ground G through springsjfl, 8l) and t, springs 21, solenoid 28 to battery B. The solenoid 28 will now operate in a manner similar to that of a buzzer, to advance the wipers 24, 25, 26 and 27 over their res ieetive bank contacts as explained in the dicscrip tion of line switch C. Upon the Wiper 27 engaging the first contact which leads to an idle selector which will be assumed to he selector E, a circuit is formed from ground (gfi iryimpfh prings and Sil, bank contact liti. hiper L7. springs Sl and H5, relav 3F?, solenoid to battery l). The resistances oi the .soll-noni 2H and the rela.;V Lits are slull that in the ahoneirrnit the relay 3S will energize while the solenoid 2S will remain iu an operated position. The rela)v 3H upon energizing. removes the line relay 37 from the line and extends the line connection to the linei rela;v Vlil olI the selectoi lil. ln addition. the rehrxv HH loruis a locking circuit for itself until u holding rireuit closed in the, selector F. The .said circuit extends 'lroin ground il through springs T9 and 80, springs titi and h5. relay 255. solenoid 2S to battery li. The line relaiv i7 made slow acting so that il will remain energized an instant after its ril-enit is opened by the, rt lastY :l5- so that time may lie allowed for :l holding circuit to he torined in the switch ahead. The circuit of the line rela)Y l-l mailr he traced from ground (1" through the lower winding ot rela); il, side switch wiper 51, (in first oosition) springs EL* and 2li, springs 8'() and il, substation A. springs 77 and 9D, springs 2l and 2li. side switch 5U tin first positionl. upper winding of relayY vll to baftery l. The lino relay 4l. upon energizing, closes a circuit through relay i7, which. in lui-n, upon energizing, a lloids the previouslyY nwntioinfli holding circuit which may' bc traced Vfrom ground (it. springs 8;). and 91, springs: it? and 2V, springs BH and Sli, rvlul iin. solenoid 2o lo battery ll. i n

The foregoing is the condition of the ccnlral oliire apparatus immediately ai'ler the receiver is removed troni lhe switch-hook at` the calling subsi ation The operation of the substation calling device for the first digit twice momentarily forces the spring (tout ol engagement with the sprii'ig T, each inne ln'enlcing the circuit ot' The line relzuY 1l-l ot' the selector lil. llaeh time the line relaiv li oi' the selector deinergizes in response to the impulses Vt'r/.inl the .substation it permits the spring Ul to flisengage the. spring l and to engage the spring fl. Since the relav 4-7 slow actilngr ils armature does not have time to full hurle to its norcia? position during the niomenlarv interruptions ol its circuit, consequently a circuit closed through the vertical magnet il?. This circuit ex tends from ground l through springs Ul and 93. springs liti and` 9T, relay 1th. lertiv cal magnet 472, side switch wiper (in tirsl' position) to battery l. The vertical magnet receives two impulses over this circuit operating to raise the switch shaft and wipers 39. l0 and #ll two steps to a position opposite the set-ond rou' or level ot bank contar-ts. The private magnet rela which is iniuded in the energizing circuit ot the verticai magnet, energized by the lrst iinpulsc, and since it is slow acting its armaturn is hold in no operatori posi 'lo 1 thrall-gir out the series ot" impnlh'os. ln its snorntcfl position tho folug' lff lost-s n` cirruit vtond ing from ground t?" through nxrrings 9S., privato 'z'auignrt 54 lo lmttory l Silit tij; nt'tcr thv last impulso i loliwref to time vortiml magnet, the relay L8 nlcnorgiges, breaking th(x (-irt'lzit of the privato magnet Si, which in turn. llolnmgixos, ntrmitting thi1 sido switch to push from first to position. Tha, pnfsmge wiper from (sommets thv n nl ningHV noi and Closes o :fisiiii limiogh thv. glow relay l) and rotary :magnet 4? This cir-Cini vx'tonfls from Ground il* tlhrou 1li intferrn #tur .r b v Y Y springs 59, rotary;r mngnot. 13, relay ik Switch Wiper tin noition) to butq tery B. The rotary magnet 43, upon nnergizing, attracts its armatura, Wliluh operates to rot-nte the Shaft, m wiiersf one Stop, :imi by means of n linger @had t@ ih@ r tary armature holds down the arnmnra oi the private magnet 5l, and opens the Circuit of its own magnet, :Lt tho intarruptol Sgn-ings 99. The nrmntnre ofthe, rfiitnry A thereupon falls bach and if the rn' upon he terminals of which the, wipe l j ust. been rotated is idle, the. :irmaure t the private magnet falls back also, pmniitting the sitio switch to prins to t inl no tion.

the. rss: trunk of `the r; ifi levoi i lun however, the primr, wiper -il imn privato lmnl sonia-:t grounded in :in i to be explained lumix Tho ongago'mfan the private wiper 1U ith :L gronneiad i met compltes a circuit extending from nontzut, lill through pri tuto, wipe-a l` agde switch wiper 53 (in nzuzoml ymtinnli vate magnet 5in-nti in mttvrj ll. Tho "ate magnet onergizoii lip" n rsa'rmit, {lowing over this ciro-oit, mtl prevmltsa the sitio switch from passing if the @hir-ri lsmilinn when the rotary ninnitfnru zillf` bouk. With they side switch thus looked in second position, tha rotary mn net will vontinoc tu ro tat/a the shaft ting ther-ahy nimm the wipers -step by step nnii tho priv-nte Wiper 4G engages a, nowgronnded fronting-,tz of in idk runk, whereupon tho privato m: energiz-'es and portons thi; shin t!) pass into third pue la. film lnmunmi-t of the side Switch wiper from wnnd. position breaks the mit oi' thv wimy magnet; 43, ami he irri; wijn-wg and 51 extend the in tion through bhelshat't. wipers 39 and 4% to the connector H.

Upon the. com lotion of the connection to the connector P the line relay mul the release relay are envagizod in the mmc Hmmm in which the vorfsgin ing wlrixs of the selector E were that einargiwi. Thu relay 7G, upon energizing, provider-i :L grammi raisin switch wiper 53 (in manna potential :11; the First selector private bank l5 :uninet mi (und to the corresponding con- 70 not in 'tho lmnii of @zich Selector which has access to the trunk line lending to the 00nneotor Il); from the bunk Contact, lOl the #iz-cuit; than wxtcnrls; through the wiper 40,

innings m2 zml lit Valmy 4T tomtcry B. This rim-niiy if; frloxml lwfore tho relay 47 has time to iivi'nvrgio nfor itis -'ormer circuit is 'brokon hf, tht: ilonergiicntin of the relay il l During Anwen baton-1in the. time thorn-ide switch of the Salomo? l to third position and the time the romy 'Jil of the connector H en orgizns, the seized trunk isprotecied by a.

ground potential oxtrmling from ground 85 25 through Springs lill ami 192 of the guarding re :y -l at ille selector E. The relay 49 is filma; :ii-,ting und is energizd in serios -with tlw` roh i magnet und remains energized for nido switch hiss poi-bwl to third position.

Then the .sulfstzluon railing device is 0p @rated for the; germ-.4% digit 2, the circuit, of the nonni-cto?` lim rola;- tl broken twice.

Sinee the rohr): ill i low acting it. (loos not 95 {loiwrgizv flaring the monwntary interruptions of its vermi-' lijf th@ iine relay G5, so that, nach time tlm inttm rieluy is donergized, n riruoit is closml 'om ground G through springs Ulf sind lf/#63 signings 107 and 108, W0

relay 7l. vel-tival magnet, 58. side switch wiper 62 (in litt position) to buttery B. The vel-tival H-iyir-t, *Q3 wceivos two impulsos ovvi' tln t :uni oawmtos to mise tlm,- awitoh slm ft :moi a position oppoffzte tlm ,second lavol of bunk contacts1 Thra wlw T1 wind: is inrlucled in serios with the vlrtifml magnet, remains in its: energicwl In fitim during entire time that impulsor: oro boing trannittrd 110 tll'gll it uml wpvlwe to riec {ik} CiV'llil of the privato mngnvt tlv The circuit for the privato nuagnvt fozhgnis from ground G1 through springs U55? :m t? private 'inzgnfet Bl to lmttviy l. poise is elrliwrefil. illu ril-hij; l opens the circuit; of thu primitif magnet 6lq which, upon flinol'gizing. permits, the sitio switch to advance 'from fil-n to sei-ond position.

The mowmwt gli {lo} nido Switch wiper 627130 from first to @omini punition transfers the5 lmttory connection from the vertical magnet 58 to the rotary mzigsw 59.

lling 'uli-Lcrbm' now operates to wli'nh tf1?? Y r me relay operates to sau-amant two lmpiww En-msgh the rotavy Mignot 59 In @F1os with thv rvlfly 7l, wherethird position) tlm short interval that :in instant; after the wipers; a5, 5G :md 57 to mi A tsr the inst iminrit digit 2 in response m5 by the shaft wi pers are rotated onto the con# tacts of the desired line. This` circuit estends from ground G" through springs 105 and 106, springs 10T and 108. through relay 71, springs lll, rotary magnet 59, side switch wiper 62 (in second position) to battery B. The relay 71 operates in response to the irnpulscs for this digit in the saine manner as for the previous digit to cause the private magnet 64 to permit the side switch to advance to the third position. By the engagement of the side switch wipers and 61 `with their third position contact points.` the line connection is completed With the called line. Upon the engagement of wiper 63 with its third position contact point, a circuit is completed through the cut-lofi' relay 112 of the called line switch. The circuit extends from ground G through side switch Wiper 63 (in third position), private Wiper 56, relay 112, solenoid 1123 to battery The resistances of the solenoid 113 and the relay 112 are such that the solenoid is not operatively energizedbut the relay 112 operates to disconnect battery and ground from the called line. The connection ot' ground G11 with the connector private bank contact of the called line prevents the called line from being seized by sonic other connector switch. By the engagement of side switch wiper 62 With its third position con tact point, the circuit of the ringer relay 66 is closed. This circuit extends from ground G12 through ringer interrupter 114. ringer relay 66, springs 115, side switch wiper 62 (in third position) to battery B. The ringer relay is energized only intermittently through the medium of the interruper 114, and operates to disconnect the calling line frpm the called line and to bridge the ringing current generator R across the called line to signal the called subscriber. Upon the response of the called subscriber his line is provided with talking current through the windings of the back bridge relay 52. The relay 72 upon energizing, closes a circuit through the relay 116, which circuit extends from ground G11 through side switch wiper 63 (in third position) springs 117` relay 116 to battery B. The relay 116, upon energizing, opens the circuit of the ringer relay 66 at the springs 115 and closes a locking circuit for itself through its springs 118 independent of the springs 117.

After the conversation is completed, the connection is released by the hanging up of the receiver at the calling substation in the following manner: When the receiver at the substation A is restored to the switch-hook, the separation of the switch-hook springs destroys the energizing circuit of the connector line relay which immediately deenergizes and opens the circuit of relay 70. r.Phe relay 70, upon deiinergizing, opens the holding circuit for the release relav 1T of the .selector ll and completes a circuit from gionnil il through springs l0() and 106, springs 10T and 1li), ott-normal springs 68, release magnet HT lo battery B. The release magnet. upon energizing, attracts its armature which removes` [he retaining doubledog from thc shu'll and its own circuit is broken at the springs us when the lsaid shaft reaches its lowest position The release rclay iT. upon ileincrgizing, closes a circuit troni ground iii Ihrongh .springs ill and 93, springs 06 and 120, release magnet 45, oti norniai springs lt? to battery l5. The release niagnel. upon energizing,y attracts its armatore which renn'ives the retaining double-dogtroin the shaft and its own circnil is opened at the springs 16 when the said shaft reaches its lowest position. In addi tion. the relay i7. upon denergizing, renwvcs the ground ti" from the circuit of re -v 5S and solenoid 26, whereupon thel relay and solenoid Q denergizethus restoring the line switch (ci to normal.

It having been described how one subscriber establishes connection and releases the same. it will nmfue explained how a connection is prevented from being made with a busy line. Ii the called number is busy, there will be a` guarding potential upon the. connector private bank Contact, just as explained in connection with the line switch C. lt is obvious` that the side-switch Wipers are in the second position during the test l'or and fitter finding that the contact desired is busy. The eolnnwftor private wiper, upon engaging this guarded Contact, closes a. circuit as follows: ground from the pri 'inte banl; Contact through privato wiper 56, side iswitch wiper 63 (in second position). springs 121. and 122, relay 123, springs 124 and lll), private magnet 64 to battery B. The :play 123, upon energizing, closes the contact ol springs 125. whereby a busy tone is sent back to the calling subscriber from the busy machine Q by way of the side switch wiper (il (in second position) thence through the calling substation A and the uppenwinding of relay 65 to battery B. A 'Further result of the energizing of relay 123 is then opening ot' thel circuit of the r0- tary magnet 55) at springs 111 and the closingr of a locking circuit t'or itself through the springs 161 and 122. The calling subscriber upon receiving the. busy signal replaces his receiver upon the receiver hook and releases the connection as hereinbefore explained.

From the foregoing it will be seen that we have devised a very simple switch, the wipers oit which always progress in one direction and at the saine time have motion in a different plane, that they may have, for example.y as herein shown, a clockwise motion und an np and down molino. We lo not therefore, Wish to viimit our-.lehre to thc pnrticulor construction slion'n.

Vilhat we cininx is:

l. In n telephone nyntein. 1V o lines.,l :i switch for connecting sziifl linee. Suini ewiieh having a shaft, o drivingr mechanism for propelling seid shaft ronnnieing tivo en raging Surfaces and n driving; member, means for driving the shaft* in one direction through the medium ol' Suid driving mem her engaging with seid Surfaces one :it :i innei :ind means for automatically continuing seni operation.

In. a iielephonc svsieni, two lines, n switch Yfor connecting eziiel Eines, seid switrh having a shaft, n driving' rnrrhzinieln for propelling seid shaft oomprieing' two en gnging Surfaoes :1nd a ririvii'igr member. means for driving the shaft always in the sinne direction through the medium of Said driving member engaging with Hnid surfaces one at gijjrne, and means for :luton'mticzillv conl'iniiraig S'aiil operation.

In a telephone syniexn, tivo lines, :i swich for connecting said iinee said switch having a Shaft, n driving morhzinism for propeliing said Shaft comprising two engaging surfaces and a driving nienilien mezfiirs 'for drivingr the Shaft in one diri-@tion through the medium of snirl driving inenihrr engaging alternately with Soni nnrfacen.

4. ln a telephone sysienn tivo lines, :a` switch for connreting seid linen, mid Snitch having a shaft. zi driving` niochnnisxn for propelling said shaft comprising two en-` gaging surfaceslmving active auctions :ind n, drivingr member, moans for driving!i the Shaft through the medium of Suid (l ning inc-inherengnging with an active eeelion in one eurface, thereby advancing the @haii to a poni tion whore the driving nirnihcr may then el factually engage un active fieriion of the other surface to drive the shzii't to :1 ponii'ion Where the drivingl member may again eifertunllv engage an activo section oi' rho first Surface to advance the shaft in the Sinne flirrection and means for operating` the meniher again to drive the shaft by engfigging with an active section of thc second surface. and means for automatically continuing said operation.

In a telephone system, two lines, a switch for Connecting seid lines, nnifl switch having a shaft, a driving mechanism for propelling said shaft comprieing two en gaging Surfaces having active scrtions a` driving memberr` means for driving Jthe shaft through the medium oi Suid driving' member engaging with an active neciion of one surface, thereby arivencing the shaft to a position Where the ririving 'member muy then e'ectually engage an entire section of the other surface to drive the ehe 5t to a posiand' enerve advance the Shaft.

(i "in e teleivhone. system, tivo lines, a switch for connorting seid lines, said switch having n shaft e driving mechanism for' propelling nativi nhni coniprining two engaging snrfnccs having activo sections and a driving nnnnhrn means for driving the Hhnir through the nieriinin of said driving niernhor engingfing 'Wifh :in activo Section of one siirinoe, then-,hy advancing the shaft to :t position where tho driving;r mem-her may then eiertunlly engage an fictive section of the other Snrfnec to drive the shaft to e position where the driving member may again efeotually engage an active section of the iii-si surface to miv-inne the shaft and means if o :einig the member ngziin'to drive the flin 'it ny engnm if with an active section of the onri snreee, soir! means automatically rontinuing the operation to automatically nrlvnnoe the Shei'., seid means comprising an eiectrio oironit.

7. 'n n teleyhone system, two lines, a, switch for connecting Suid lines, said switch heaving; :i ehnit, :i driving mechanism for propoliing anni shaft comprising two eng'nginkg nnrinree having active Sections and :i driving nienihefz means for driving the .sh-ift through ihn medium of said driving ine-ini. Y,r engaging active section of one su' 'zum therehv advancing theshaft to i punition Where the driving member may thon elinrllmfiv engage an eciive sec-tion of the'L other snrince ig `,vivo the shaft to nfposilion n'r'rre the lrignig member may again etre-ctn: .v runnin* nn active section of the lient surfer-ef io mimmo the shaft and means for opernlingr ino nirinher again to drive the nhui't h v engaging with an active sec tion of the seconi surface, said means auto nintirsillv ernitinuing the operation to automatically nilvaine Ilhe: shaft, lsnid means comprising an electric circuit and a circuit interrnpter,

F, ln n telephmie system, two lines, a switch for ommen-ing said lines, seid switch inning` n shaft, nn electromagnetic driving Inechfmisin i'herefnr for propelling Said Shaft ronnirisinf; two engaging surfacennd alsA c( .uprising two sets of teeth and a driving member, means for driving the shaft through the lnedium of said driving memhcr engaging with said sets one at, a time,

l and means for automatically continuing said operation.

l0. In a telephone system, lines. a switch for connecting arid lines, said switch ha ving a shaft.l an eleetronnignetic driving mechanisn'i for said shaft comprising two sets of teeth and a driving member. means for driving thc shat't through the medium of said driving member engaging with said sets one at a time, and means for automatically continuing said operation.

1l. ln a telephone s vstcm, lines. a switch for connecting said lines. said switch having a sha't't. a driving mechanism 'tor said shaft comprising two sets of teeth and a driving member. means t'or driving the shaft always in the sannudircction Athrough the medium ot' said driving member engaging with said sets one at a time. and means t'or automatically continuing said ol'icration.

l2. ln a tclcphonc system. lines. a switch for connecting said lines. said switch havinga shaft. a driving mechanism l'or said shaft comprising two sets of teeth and a driving member. means For dri\ ing the shaft through the medium ot' said driving nicmber engaging with said sets alternately one at a time, and means for automatically continuing said operation.

13. In a telephone system` lines, a switch for connecting said lines. said switch having a shaft. a driving mcchanisn'i for said shaft comprising two sets ot' teeth staggered with respect to cach other and a driving member, means for driving tlie shaft through the 40 medium of said driving member engaging with a tooth in one set thereby advancing the shaft to a position vwhere the driving member may ctt'cctnallyY engage a tooth in the other set to drive thc shaft to a position where. the driving member may then effectuallyY engage a tooth in the first setf and means for operating said member. and means for automatically continuing said operation.

14. In a telephone system. lines, a switch for connecting said lines. said switch having a shaft. a driving mechanism for said shaft comprising two sets oT`tccth staggered with respect to each other and a driving member.` means for drivingthc shaft, through the medium of said driving member engaging a tooth in one set thereby advancing the shaft to a position where thc driving member may effectually engage a tooth in the other set to drive the shaft to a position Where the driving member may then effectually engage a tooth in the first set and means for operating said member, said means antomaticallyr continuing thc operation.

15. In a telephone system, lines, a switch 66 for connecting said lineg. said switch having a shaft, a driving mechanism for said shaft comprising two sets of teeth sta ered f with respect to each other and a rlving member. means for operating said member 70 to drive he shaft by engaging a. tooth in one set thereby advancing the shaft to a position where the driving .member ma)v eft'cctually engage a tooth in the other set f to drive the shaft to a position where the drivingl member may then efi'cctually engage a tooth in the first set and means for operating said member. and means for autoi mati ally continuing the operation, said'V means comprising an electric circuit.

1G. ln a telephone system. lines. a switch tor connecting said lines. said Switch hav-` ing a shaft.. a driving mechanism for Said shaft comprising two sets ot teeth staggered with respect to each other and a driving nlcmbcr. means for operating said member to drive the shaft b v engaging a tooth in one set thercb)v advancing the shaft to a position where the driving member may eftcctnallv engage a tooth in Ythe other set to 00 drivi` thc yshaft to a position where the driving member ma)v then eti'cctnall)v engage a tooth in the first set and means for operatingl said member. and means for automaticallir continuing the operation. said means 96 comprising an electric circuit and a circuit interrupter.

17. ln a telephone system. a line. a series ot' lines associated therewith, a switch for connecting said line with an v one of the 100 lines ot said series. said switch provided with connecting means for that` purpose` a driving mechanism for said connecting means comprising a magnet and a shaft.

a set of wipers for said line. a 'bank of ter- 105 minalsl for said series associated with said wipers. and means toroperating said driving mechanism to advance the wipers upon the encrgization as well as upon the. deinergization of themagnet. whereby thc wipers ,110 are at one til-ne carried into engagement with the bank and at another time liftedout of engagement with the bank. said magnet controlled hv said wipers to automatically continue said operation.

18. Ina telephone Systemma line, a switch for said line having abnk. said bank having sets of line terminals. a' set of wipers in said switchl for connecting the line with a set ot terminals, a controlling device indi- 120 vidnal to said switch for operating said wipers to connect and disconnect the line` from the bank contacts and for'advancing said wipers always in the same direction with one motion to establish the connection 18B and another motion to break the connection, said device controlled by said -wipers to automatically continue 4said operation.

19. In :i telnp'mm s yslmn. :l milling iine, trunk lines, a non-numerical switch for c011- nccting thv nailing' lim with :my onu of Said trunk linea, :i plurality of wipers for said switch adapted to vnggngo cimtactsassociatml with said trunk linux, mi operating' magnet for Said switch 'for coritrnling the operation of thb sume, means controllori over thv, calling line fm' initiating the operation of. said switch, and Lutonmiiv ummm ,for von tiriuiug the operation until one of said Wipers ungugfe u` normal groum'lvd contuci, :L circuit (timed thereby over smother one qi Said wipers mholding the operating mug net, rfnergized.

Signnd 'by im at (,lhicagn, Cook county, Illinoisi, this 18H1 day of Septmnber, 1914. ALEXANDER E. KEITH. JOHN G. BLESSTNG. Witnesgef Himmmr W. KRACKE, (hxmma GANUGHOWSKL 

